Spada Jewellers — Education
Jewellery Metals Guide
Gold, white gold, rose gold, platinum and silver — purities, properties and what to recommend.
Yellow Gold
Yellow gold is alloyed with silver, copper and zinc to achieve workability and durability. The karat number tells you how many parts out of 24 are pure gold — the rest is alloy.
Purity by Karat
For lab diamond settings, 18K yellow gold maximises colour contrast on fancy yellow stones. 14K is the practical choice for solitaire rings that will be worn daily.
White Gold
White gold is yellow gold alloyed with white metals — typically palladium or nickel — then coated with rhodium to achieve a bright, silvery finish.
Composition
- White gold is NOT naturally white — the colour comes entirely from the rhodium plating over the alloy.
- Without replating, white gold gradually shows a slight yellow/warm tint as the base alloy becomes visible.
- 18K white gold in palladium alloy is the premium choice — hypoallergenic, bright, and holds rhodium longer.
When customers ask about white gold vs platinum, the key distinction is maintenance: white gold needs periodic replating, platinum does not. Price point and weight preference usually decide it.
Rose Gold
Rose gold gets its warm pink hue from a higher copper content in the alloy. The more copper, the deeper the rose tone. No plating required — the colour is inherent to the metal.
Copper Content by Karat
14K rose gold offers the best balance — a warm, visible rose tone with good purity. 18K rose gold is subtler in colour and carries a higher resale perception for fine pieces.
Platinum
Platinum is a naturally white, rare metal used in fine jewellery at 95% purity. It requires no plating, is hypoallergenic, and is significantly denser than gold.
Purity
- Platinum does not tarnish or corrode — it maintains its white colour indefinitely without maintenance.
- Scratches on platinum displace metal rather than remove it — unlike gold, very little material is lost over time.
- Platinum prongs hold diamonds more securely than gold — preferred by gemologists for precious stone settings.
Platinum is the correct answer when a customer asks "what's the best metal?" — for longevity, security and prestige. Position it on purity and permanence, not just price.
Silver
Sterling silver (925) is 92.5% pure silver alloyed with copper for durability. The most affordable precious metal — excellent for fashion and statement pieces.
Purity
- Fine silver (999) is too soft for most jewellery settings — rarely used except in artisan/hand-formed pieces.
- Silver-plated jewellery has a base metal core — not sterling. Look for the 925 hallmark to confirm genuine sterling.
- Store in an airtight bag or anti-tarnish cloth to extend polish between wears.
- Avoid chlorine (pools, cleaning products) — it accelerates tarnish and can pit the surface.
Silver is an entry point, not a compromise — position it as the right material for fashion-forward designs and volume buys. Argentium is worth recommending for higher-margin pieces where tarnish resistance matters.
Purity Guide
Quick-reference table for karat, millesimal fineness, hallmarks and purity percentages across all common precious metals.
Gold — Karat to Fineness
| Karat | Purity | Hallmark | Parts Gold (of 24) |
|---|---|---|---|
| 24K | 99.9% | 999 | 24/24 |
| 22K | 91.6% | 916 | 22/24 |
| 18K | 75.0% | 750 | 18/24 |
| 14K | 58.5% | 585 | 14/24 |
| 10K | 41.7% | 417 | 10/24 |
| 9K | 37.5% | 375 | 9/24 |
Platinum
| Grade | Purity | Hallmark | Notes |
|---|---|---|---|
| Platinum 950 | 95% | PT950 | Fine jewellery standard |
| Platinum 900 | 90% | PT900 | Common in Japanese market |
| Platinum 850 | 85% | PT850 | Less common, entry-grade |
Silver
| Grade | Purity | Hallmark | Notes |
|---|---|---|---|
| Fine Silver | 99.9% | 999 | Too soft for most jewellery |
| Argentium | 93.5% | 935 | Tarnish-resistant alloy |
| Sterling Silver | 92.5% | 925 | Jewellery standard |
When a customer asks "is this real gold?" — look for the hallmark stamp inside the band. 375 = 9K, 585 = 14K, 750 = 18K. No stamp typically means plated or base metal.